How fast is your bus? WMATA maps bus speeds

As Bob Thomson reported on Sunday, WMATA has created maps showing the average speeds of buses across the region. These maps help illuminate where we could most help riders and also save money through strategic placement of bus lanes, queue jumpers, signal priority and more.

I’d been able to see early drafts of this map from WMATA officials. They have now finished the analysis and have posted it publicly.

The original maps showed slow buses in red, up to faster buses in green. However, the intermediate yellow bus lines were hard to see, and red to green is bad for color blind readers. Therefore, I’ve swapped the red and blue channels so that these maps show the bus speeds from green (fastest) through cyan to dark blue (slowest).

According to my color blindness simulator Photoshop plugin, color blind people should be able to distinguish all of these colors; the rivers and the fast buses might be similar colors, but they’re easy to tell apart in other ways.

Closer to the core, the bus speeds are generally slower. That’s a consequence partly of congestion, but also partly from bus stop density. Since there are more destinations and more riders in the central areas, there are more bus stops, and those stops have more riders, which take time to load and unload. DC could reduce some, but there will still be more and speeds will therefore be slower. It’s where some lines are slower than their neighbors, sometimes much slower, that the difference becomes particularly useful.

Here are maps distinguishing the AM and PM peak times:

Based on this analysis, WMATA has identified a few key corridors ripe for improvement. These are areas where there are very slow buses coupled with high frequencies of buses. This is where a bus lane, queue jumper at an intersection, and/or signal priority could create the greatest time savings for the largest number of residents, and save the most money in operating costs as well.

This spreadsheet shows the full calculations. It includes the top ten corridors in each of the three jurisdictions for AM and PM peaks and all week, ranked by multiplying the number of buses per hour (for peak periods) or per week by the average speed over that link.

Local jurisdictions keep saying they are very strapped for cash and can’t afford Metro extensions, light rail lines, big road widenings, new freeways, and more. Optimizing these high-priority corridors for efficient bus movement is the single most cost-effective, quick low-hanging fruit for improving mobility. Let’s get on it, DOTs!